drm/radeon: fix backend map setup on 1 RB sumo boards

Need to adjust the backend map depending on which
RB is enabled.

Fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=892233

Reported-by: Mikko Tiihonen <mikko.tiihonen@iki.fi>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 112da9b3c8ee..2270867d8551 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2044,9 +2044,20 @@ static void evergreen_gpu_init(struct radeon_device *rdev)
         WREG32(HDP_ADDR_CONFIG, gb_addr_config);
         WREG32(DMA_TILING_CONFIG, gb_addr_config);
 
-        tmp = gb_addr_config & NUM_PIPES_MASK;
-        tmp = r6xx_remap_render_backend(rdev, tmp, rdev->config.evergreen.max_backends,
-                                        EVERGREEN_MAX_BACKENDS, disabled_rb_mask);
+        if ((rdev->config.evergreen.max_backends == 1) &&
+            (rdev->flags & RADEON_IS_IGP)) {
+                if ((disabled_rb_mask & 3) == 1) {
+                        /* RB0 disabled, RB1 enabled */
+                        tmp = 0x11111111;
+                } else {
+                        /* RB1 disabled, RB0 enabled */
+                        tmp = 0x00000000;
+                }
+        } else {
+                tmp = gb_addr_config & NUM_PIPES_MASK;
+                tmp = r6xx_remap_render_backend(rdev, tmp, rdev->config.evergreen.max_backends,
+                                                EVERGREEN_MAX_BACKENDS, disabled_rb_mask);
+        }
         WREG32(GB_BACKEND_MAP, tmp);
 
         WREG32(CGTS_SYS_TCC_DISABLE, 0);